Abstract
The 24 GHz continuous-wave (CW) Doppler radar sensor (DRS) is widely used for measuring the instantaneous speed of moving objects by using a non-contact approach, and has begun to be used in train-borne movable speed measurements in recent years in China because of its advanced performance. The architecture and working principle of train-borne DRSs with different structures including single-channel DRSs used for freight train speed measurements in railway freight dedicated lines and dual-channel DRSs used for speed measurements of high-speed and urban rail trains in railway passenger dedicated lines, are first introduced. Then, the disadvantages of two traditional speed calibration methods for train-borne DRS are described, and a new speed calibration method based on the Doppler shift signal simulation by imposing a signal modulation on the incident CW microwave signal is proposed. A 24 GHz CW radar target simulation system for a train-borne DRS was specifically realized to verify the proposed speed calibration method for a train-borne DRS, and traceability and performance evaluation on simulated speed were taken into account. The simulated speed range of the simulation system was up to (5~500) km/h when the simulated incident angle range was within the range of (45 ± 8)°, and the maximum permissible error (MPE) of the simulated speed was ±0.05 km/h. Finally, the calibration and uncertainty evaluation results of two typical train-borne dual-channel DRS samples validated the effectiveness and feasibility of the proposed speed calibration approach for a train-borne DRS with full range in the laboratory as well as in the field.
Highlights
High-speed railway has had a rapid development in recent years in China and the total mileage of high-speed railway passenger dedicated lines has exceeded 35,000 km, accounting for about 70% of the world’s high-speed railways in commercial service
The simulated speed range of the simulation system was up to (5~500) km/h when the simulated incident angle range was within the range of (45 ± 8)◦, and the maximum permissible error (MPE) of the simulated speed was ±0.05 km/h
To validate the effectiveness and feasibility of the proposed speed calibration method, two typical train-borne dual-channel Doppler radar sensor (DRS) samples were chosen to be calibrated in full range by using the realized simulation system to evaluate its technical performance
Summary
High-speed railway has had a rapid development in recent years in China and the total mileage of high-speed railway passenger dedicated lines has exceeded 35,000 km, accounting for about 70% of the world’s high-speed railways in commercial service. Traditional train-borne movable speed measurement approaches of conventional trains usually rely on a single kind of wheel speed sensor including an axle-mounted wheel speed sensor, eddy current speed sensor, or Hall speed sensor, etc These kinds of wheel speed sensors measure the rotational speed of the train wheel to indirectly calculate the train speed and covered distance. One disadvantage of these wheel speed sensors is that it may lead to large deviations and even no results in train speed measurement when wheel slippage occurs, which may cause a serious impact on train operation safety. Another disadvantage is that these wheel speed sensors measure the train speed by using a contact approach, which may suffer from the problem of excessive wear and tear, especially at high speed
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
